The senses provide us with basic information about our surroundings. At a first level, sensory information can be broken down into its constituent parts each of which, in turn, can be perceived as being somewhere above a threshold level. For smell we can deconstruct perfume into different characteristics and perceive the relative preponderance of each. For odour, the key ‘dimensions’ of the sensory world are: threshold, intensity and character. In this way we can derive a quantitative or semi-quantitative descriptive analysis of a smell. However odours are also powerful drivers of mood and emotion and in many cases our primary response to odours is emotional.
Olfactory information feeds directly through the olfactory bulb into the limbic system, the emotional heart of the brain. This finding reinforces the conclusion that odour has a powerful ability to evoke emotions. Other senses confer sensory information on a far more factual level. The primacy of vision emphasises this.
Vision provides a sophisticated ability to resolve colour, shape, size, distance, movement, direction, texture; it informs recognition. It can be enjoyed at an artistic or abstract level through introspection but the first experience is factual, sensory information. The higher-level perceptions follow.
For odour, the process is generally reversed. Odour recognition in untrained subjects is low. Memory for odours is poor, certainly less than memory for words and pictures. The primary reactions to odour are hedonic, associative, and emotional. Once these responses bring an odour to the attention of the subject it may be further characterised, for example, with respect to its sensory dimensions.
Emotions (such as joy) are transitory, brief events. An episode will rarely last more than a minute.
Moods (such as happiness) can last much longer, even hours. They are background states which provide a context for emotions.
Moods can be both enablers and barriers. If the subject is in a happy mood then it is easier for them to experience joy. Conversely if the subject is in a sad mood it is more difficult for them to feel joy. They are inputting into our feelings of well-being, which in turn can be seen as the integration of emotional and physical inputs that come together to define the organism's state.
Our moods reset the baseline for feeling emotions. Moods and emotions may act as motivators encouraging us to act in ways that increase our survival chances and enjoyment. The structure of moods has been described by Russell (1980) and E Diener & R J Larsen (1984) who were able to classify the spectrum of emotions in terms of their pleasantness and the degree of activation involved. The circumplex model (see L. Feldman Barrett and J. A. Russell, 1999, Current Directions in Psychological Science, 8, p. 11 (American Psychological Society)) describes affect in terms of the two orthogonal dimensions of valence and activation. Activated, pleasant moods included states of invigoration and stimulation. Deactivated pleasant moods included Relaxed. Negative activated moods could be typified by Annoyed or Nervous, while negative deactivated moods could be exemplified by Boredom. The key dimensions of mood would be Stimulated-Calm and Happy-Sad. We have found that fragrances can enhance moods, and we describe here how fragrances can be specifically formulated to enhance activated, pleasant moods.
Context can have an influence on the moods evoked by odours and this is particularly relevant for positive, activated smells. This has largely been driven by associations with the usage of different fragrance classes in different consumer product applications, such as lemon in dish wash products. It is a phenomenon akin to that found in taste when a yellow drink delivers an expectation of ‘lemon-ness’. The colour primes the taste and odour expectation.
The present invention is limited to the intrinsic mood effects of odours, and does not address those that may arise from additional external information which may be present in consumer products, and which will have an additional priming effect, for example, as in aromatherapy. Aromatherapy teaches that essential oils can provide stimulating effects. In its traditional form, an aromatherapist applies oils to the patients skin with massage to deliver benefits including mood. Occasionally aromatherapists will mix oils to achieve the desired effects. The use of aromatic plants and oils dates back to ancient times. Holy perfumes were used as incense or aromatic oil to evoke a spiritual atmosphere or heighten spiritual awareness. In the times of the Assyrians and the Babylonians aromatic oils were popular in spas and baths. These people believed that they could use fragrant essences to preserve their health and thus live longer. Traditionally the art of aromatherapy is concerned with healing. It has been shown more recently that essential oils are absorbed through the mucosas of the mouth, nose, pharynx, gastro-intestines and also through intact skin. The oils interact with certain cell membrane lipids thus causing, among other effects, an alteration of the calcium-ion-channel-function. Besides this direct molecular action there is also stimulation in the limbic system in the brain which is responsible for all our emotions and sensations such as anxiety, fear, feelings of wellness, harmony and sexual desires. Through this mode of action aromatherapy has several therapeutic benefits, for beauty, general well-being, emotional help and certain illnesses. Treatments may be used as an effective method of stress relief or they may help people to become more energised.
Although these practices benefit from the aroma of the materials used, it is not clear that the primary benefits arise from the aromas themselves or for example, the skin contact, the massage, the expectations of the subject, and/or the teachings of the aromatherapist. There is little consistency between the odours of essential oils, reputed to have stimulating effects.
Our research has shown that the ability of odours to enhance mood is related to their complexity. Complex odours in a similar olfactory category were generally more effective than simple blends, and simple blends were more effective than single materials and oils. In experiments, which involved pure smelling, as opposed to skin application and massage, the more complex creations outperformed their simple analogues in terms of mood generation. In all cases, perfumes developed according to the skills of the art, outperformed the simpler aromatherapy oils (see Example section).
Apart from the widespread usage of aromatherapy there are few disclosures in the literature that reveal how to design complex fragrances to deliver target emotional benefits. European patent number EP 1,343,466 describes perfumes that will aid relaxation and calming, and co-pending application PCT/GB2006/002285 describes how to formulate enlivening perfumes using a relatively limited perfume ingredient palette. U.S. Pat. No. 7,097,863 discloses a process for relaxing the back, shoulder or neck muscles through the inhalation of aroma notes described as rosy, floral, musky, ambery, sweet and/or powdery. EP 1,218,023 relates to fragranced personal care compositions that may be used to calm mammals, including humans and in particular, humans aged between about 1 day to 12 years. These compositions include sensory components comprising a specified essential oil together with particular perfume ingredients.
The sensory interactions of perfume ingredients are well known by those in the art to be very complex, and many years of training are required before perfumers become competent to work well with a wide repertoire of ingredients. Similar comments apply to the mood effects delivered by perfumes, but surprisingly it is possible to formulate perfumes with desirable emotional benefits using the creative rules described below.